Recently I saw a video by Tiago Forte which seemed to me very interesting about taking book notes. It is an interview with Alex Wieckowski from Alex & Books in which he describes his method to get the most out of the book.
TLDR
- Highlight the most interesting parts inside the book.
- Create your own table of contents at the first page of the book.
- Write down summary of the book in your own words at the last page of the book.